slack_conversations_replies

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so the safety profile is covered structurally. The description adds the important semantic that ts identifies a thread anchor, but says nothing about pagination behavior, ordering, or rate limits that would enrich the picture.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences, front-loaded with the action and followed by the one input detail that matters. No filler or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For an 8-parameter read tool with no output schema, the description leaves notable gaps: nothing about pagination via cursor, time-window filtering with oldest/latest, or the shape of the returned thread. The thread-anchor guidance is helpful but the definition is only minimally complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so all eight parameters are documented in the schema itself, making 3 the baseline. The description's note about ts is essentially a restatement of the schema's 'Prefer the parent message's ts' and adds nothing about limit, cursor, oldest, latest, or inclusive.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource: fetch a thread of messages. An agent can tell this apart from most siblings, though it never explicitly contrasts itself with slack_conversations_history, which is the nearest alternative for reading channel messages.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives one concrete usage instruction (pass the parent message's ts as the thread identifier), which is more than implied usage. However, it never states when to use this versus slack_conversations_history or how to obtain a parent ts, so routing still requires inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.